MID 122 - CID 0168 - FMI 01
CAT Comm Adapter 3 478-0235 Diagnostics for Caterpillar
This code is generated when Product Link detects a battery voltage below 11 VDC.
Test Step 1. Check the system voltage of the PRODUCT LINK module.
Start the engine and run it at high idle for 5 to 10 minutes. Measure the system voltage between the "No Switching Power" and "Ground" contacts. Pin 52 is the "No Switching Power" terminal, and pin 65 is the "Ground" terminal.
Expected Results: 24 VDC system voltage: 27 VDC to 29 VDC. 12 VDC system voltage: 13 VDC to 15 VDC. Results:
• OK - Voltage is correct. Clear this diagnostic code and check for any other diagnostic codes. Stop.
• Exception - Voltage is incorrect. Proceed to Test Step 2.
Test Step 2. Check the alternator.
Run the engine at high idle for 5 to 10 minutes. Measure the voltage output at the battery terminals.
Expected Result: For a 24 VDC system, the voltage range should be 27 VDC to 29 VDC. For a 12 VDC system, the voltage range should be 13 VDC to 15 VDC.
Result: • OK - Voltage is correct. Proceed to Test Step 3.
Caterpillar ET 2025A & 2019C Electronic Technician Diagnostic Software Download and Installation
• Abnormal - Voltage is incorrect.
Repair: Repair or replace the alternator.
Stop Test Step 3. Check the battery voltage.
Turn the ignition switch to the off position. Measure the voltage at the battery terminals.
Expected Result: For a 12 VDC system, the voltage should be 12 VDC to 15 VDC. For a 24 VDC system, the voltage should be 24 VDC to 27 VDC.
Results:
• OK - Voltage is between 12 VDC and 15 VDC, or between 24 VDC and 27 VDC.
Repair: The Product Link may be faulty. Recheck the system before replacing the Product Link. The Product Link is rarely the root cause of diagnostic codes. See System Operation, Troubleshooting & Repair, Testing & Adjustment, "Electronic Control Module (ECM) - Replacement". After replacing the Product Link, recheck the system and the status of the diagnostic codes.
12.2021 Caterpillar ECM ECU Flash Files Full Set Download
Stop • Abnormal - Voltage is not between 12 VDC and 15 VDC, or between 24 VDC and 27 VDC.
Repair: Refer to the specific manual, REHS0354, "Charging System Troubleshooting & Repair". If the problem persists, the Product Link may be faulty. Recheck the system before replacing the Product Link. The Product Link is rarely the root cause of diagnostic codes. Please refer to System Operation, Troubleshooting and Troubleshooting, Testing and Adjustment, "Electronic Control Module (ECM) - Replacement". After replacing the Product Link, recheck the system and the status of diagnostic codes.
